Conclusions
These results clearly show that TiO2 NPs have no mutagenic effects on the liver, even though the particles remain in the liver long-term.
Results
Male gpt delta C57BL/6 J mice were administered with various doses of TiO2 NPs weekly for 4 consecutive weeks. The long-term mutagenic effects on the liver were analyzed using gpt and Spi- mutation assays 90 days after the final injection. We also quantified the amount of titanium in the liver using inductively coupled plasma mass spectrometry and observed the localization of TiO2 NPs in the liver using transmission electron microscopy. Although TiO2 NPs were found in the liver cells, the gpt and Spi- mutation frequencies in the liver were not significantly increased by the TiO2 NP administration. Conclusions: These results clearly show that TiO2 NPs have no mutagenic effects on the liver, even though the particles remain in the liver long-term.